I think you're missing the point. The IRS has already received your 1099/W2/etc and thus it knows (a) your income, and (b) how much in taxes you've already paid. By then having the IRS start your tax return for you, you would no longer have to fill in that info. The IRS makes free forms available already. Besides, are there actually people so stupid that they would give their SSN/info to a site like that?